Granted Patent B2

US 7,355,931 · App. 10/915,232 · Granted Apr 8, 2008

Abstract

Claims (30)

1. A method for calibrating a center error signal in an optical disc system, comprising the steps of:

(A) measuring a peak-to-peak value of said center error signal;

(B) computing a nominal peak-to-peak value of the center error signal after locking to a particular track of an optical disc;

(C) computing said nominal peak-to-peak value of the center error signal for a run-out condition; and

(D) generating a calibration gain for a current value of said center error signal in response to said peak-to-peak value and said nominal peak-to-peak value, wherein said calibration gain compensates for different disc reflections to provide stability to said center error signal.

2. The method according to claim 1 , wherein said optical disc comprises a plurality of tracks.

3. The method according to claim 1 , wherein said run-out condition comprises a number of peaks of a tracking error signal.

4. The method according to claim 3 , wherein said tracking error signal is generated using differential phase detection.

5. The method according to claim 3 , wherein said tracking error is generated using differential push pull.

6. A computer readable medium comprising code executable on a computer, said code configured to execute the steps of claim 1 .

7. The method according to claim 6 , wherein said computer readable medium comprises firmware.

8. The method according to claim 1 , wherein said method is implemented in hardware.

9. The method according to claim 1 , wherein said method is implemented partially in hardware and partially in firmware.

10. The method according to claim 1 , wherein said calibration gain is calculated within an initial number of rotations of said optical disc.

11. An apparatus for calibrating a center error signal in an optical disc system comprising:

means for measuring a peak-to-peak value of said center error signal;

means for computing a nominal peak-to-peak value of the center error signal after locking to a particular track of an optical disc;

means for computing said nominal peak-to-peak value of the center error signal for a run-out condition; and

means for generating a calibration gain for a current value of said center error signal in response to said peak-to-peak value and said nominal peak-to-peak value, wherein said calibration gain compensates for different disc reflections to provide stability to said center error signal.

12. The apparatus according to claim 11 , wherein said apparatus is implemented in hardware.

13. The apparatus according to claim 11 , wherein said apparatus is implemented partially in hardware and partially in firmware.

14. The apparatus according to claim 11 , wherein said calibration gain is calculated within an initial number of rotations of said optical disc.

15. An apparatus comprising:

a sled motor configured to adjust a position of an optical housing in an optical disc system in response to a control signal;

a control circuit configured to generate said control signal in response to a plurality of photo-diode signals; and

a photo-diode distribution portion configured to generate said photo-diode signals, wherein said control circuit comprises

(a) a center error creation circuit configured to generate a center error signal in response to said photo-diode signals;

(b) a gain circuit configured to calibrate said center error signal; and

(c) a control circuit configured to generate said control signal in response to said calibrated center error signal, wherein said calibration of said center error signal is configured to compensate for different disc reflections to provide stability to said center error signal.

16. The apparatus according to claim 15 , wherein said calibration of said center error signal occurs within an initial number of rotations of an optical disc.

Assignments (10)